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Fix junk data being returned with incremental selection transfers

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* src/xselect.c (receive_incremental_selection): New arg
REAL_BYTES_RET.  Set it to the actual size instead of using the
size of the array after it was grown by xpalloc.
(x_get_window_property_as_lisp_data): Adjust call to
receive_incremental_selection.
This commit is contained in:
Po Lu 2022-08-30 19:27:39 +08:00
parent db6e574567
commit 0bf5463f81
1 changed files with 29 additions and 5 deletions
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34
src/xselect.c
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@ -1567,7 +1567,8 @@ receive_incremental_selection (struct x_display_info *dpyinfo,
unsigned char **data_ret,
ptrdiff_t *size_bytes_ret,
Atom *type_ret, int *format_ret,
unsigned long *size_ret)
unsigned long *size_ret,
ptrdiff_t *real_bytes_ret)
{
ptrdiff_t offset = 0;
struct prop_location *wait_object;
@ -1622,7 +1623,8 @@ receive_incremental_selection (struct x_display_info *dpyinfo,
if (tmp_size_bytes == 0) /* we're done */
{
TRACE0 ("Done reading incrementally");
TRACE1 ("Done reading incrementally; total bytes: %"pD"d",
*size_bytes_ret);
if (! waiting_for_other_props_on_window (display, window))
XSelectInput (display, window, STANDARD_EVENT_SET);
@ -1652,6 +1654,19 @@ receive_incremental_selection (struct x_display_info *dpyinfo,
memcpy ((*data_ret) + offset, tmp_data, tmp_size_bytes);
offset += tmp_size_bytes;
/* *size_bytes_ret is not really the size of the data inside the
buffer; it is the size of the buffer allocated by xpalloc.
This matters when the cardinal specified in the INCR property
(a _lower bound_ on the size of the selection data) is
smaller than the actual selection contents, which can happen
when programs are streaming selection data from a file
descriptor. In that case, we used to return junk if xpalloc
decided to grow the buffer by more than the provided
increment; to avoid that, store the actual size of the
selection data in *real_bytes_ret. */
*real_bytes_ret += tmp_size_bytes;
/* Use xfree, not XFree, because x_get_window_property
calls xmalloc itself. */
xfree (tmp_data);
@ -1674,10 +1689,14 @@ x_get_window_property_as_lisp_data (struct x_display_info *dpyinfo,
int actual_format;
unsigned long actual_size;
unsigned char *data = 0;
ptrdiff_t bytes = 0;
ptrdiff_t bytes = 0, array_bytes;
Lisp_Object val;
Display *display = dpyinfo->display;
/* array_bytes is only used as an argument to xpalloc. The actual
size of the data inside the buffer is inside bytes. */
array_bytes = 0;
TRACE0 ("Reading selection data");
x_get_window_property (display, window, property, &data, &bytes,
@ -1718,10 +1737,15 @@ x_get_window_property_as_lisp_data (struct x_display_info *dpyinfo,
calls xmalloc itself. */
xfree (data);
unblock_input ();
/* Clear bytes again. Previously, receive_incremental_selection
would set this to min_size_bytes, but that is now done to
array_bytes instead. */
bytes = 0;
receive_incremental_selection (dpyinfo, window, property, target_type,
min_size_bytes, &data, &bytes,
min_size_bytes, &data, &array_bytes,
&actual_type, &actual_format,
&actual_size);
&actual_size, &bytes);
}
if (!for_multiple)